1. Malmaison, Oxford

We're so used to seeing former hospitals/churches/schools stripped and reinvented as luxury flats/gastro pubs/art spaces, it came as no surprise when Malmaison announced that it had transformed Her Majesty's Prison, Oxford into its eighth hotel. But there is something quite shocking about actually staying there – the cells/bedrooms are so plush (rich velvet and dark sexy colours) that you almost forget. Until you go to open the original heavy cell door and step out on to A wing.

2. Napier Prison, New Zealand

Decommissioned in 1993, the prison was reopened in 2002 to offer tours and backpacker accommodation. You can have it the easy way — staying in modest comfort in a converted cell (double with loo and sink), or a dormitory. Or you can have it the hard way with a stretch in an original unpadded cell.

3. Karosta prison, Liepaja, Latvia

"An opportunity to stay overnight on real prisoners' benches and mattresses," according to the website, which goes on to boast that it is "unfriendly, unheated, uncomfortable". There are absolutely no comforts laid on at this naval jail built in 1905 to house the czar's mutinous sailors. New management took over in the 1970s: the KGB. Sounds miserable? It is. Perfect for stag dos.

The Old Jail, Mount Gambier, Australia

The former South Australian State Prison closed in 1995 and has been kept as authentic as possible, so facilities are very basic, including shared showers. There is, however, Turnkey restaurant for a spot of porridge. A$22 a night for dormitory, double with toilet.

Langholmen Hotel, Stockholm, Sweden

The old Crown Prison closed in 1975 and was reopened as a hotel in 1989. The original heavy cell doors have been retained, though behind them things have changed a little. The bars have been removed from the windows, and stylish bathrooms have been attached. The restaurant is rated one of the best in Stockholm.